Is There Water on Venus?

[/caption]
When astronomers first pointed their rudimentary telescopes at Venus, they saw a world shrouded in clouds. Here on Earth, clouds mean water, so early astronomers imagined a tropical world with constant rainfall. The truth, of course is that the thick atmosphere on Venus is made almost entirely of carbon dioxide. In fact, the atmospheric pressure on the surface of Venus is 92 times more than what you would experience on Earth. If the clouds are carbon dioxide, is there water on Venus.

Well, there isn’t any water on the surface of Venus, in form of rivers, lakes or oceans. The average temperature on Venus is 461.85 °C. Since water boils at 100 °C, it couldn’t be on the surface. But could water be in the clouds and atmosphere of Venus?

Astronomers have detected that the atmosphere of Venus consists of 0.002% water vapor. Compare that to the Earth’s atmosphere, which contains 0.40% water vapor.

Scientists think that Venus had a similar formation to Earth, and it was certainly bombarded by the same comets that delivered vast quantities of water to our early planet. So why has Venus lost its water, while Earth kept its water? Recent observations by ESA’s Venus Express spacecraft found that Venus has a trail of hydrogen and oxygen atoms blasted away from the planet by the Sun’s solar winds. Every second, there are 2 x 1024 hydrogen atoms streaming away from Venus. The Earth’s magnetosphere protects our atmosphere from the Sun, channeling the solar wind around the planet, and keeping it from reaching our atmosphere.

The Earth’s magnetosphere is generated by the convection of material deep inside the Earth. This happens because the large temperature difference between the outer core and the inner core. At some point, plate tectonics on Venus ceased, and the planet stopped releasing as much heat from the interior. Without a high temperature gradient, its inner convection stopped, taking away its planet-wide magnetosphere.

It’s estimated that Earth’s atmosphere and surface has 100,000 times as much water as Venus. And if we didn’t have our protective magnetosphere, we’d be losing our water too.

We have written many articles about Venus for Universe Today. Here’s an article about Venus’ wet, volcanic past, and here’s an article about how Venus might have had continents and oceans in the ancient past.

Want more information on Venus? Here’s a link to Hubblesite’s News Releases about Venus, and here’s NASA’s Solar System Exploration Guide to Venus.

We have recorded a whole episode of Astronomy Cast that’s only about planet Venus. Listen to it here, Episode 50: Venus.

Reference:
NASA Ask an Astrophysicist: Water on Venus

Fraser Cain

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay. Here's a link to my Mastodon account.

Recent Posts

Flowing Martian Water was Protected by Sheets of Carbon Dioxide

Mars' ancient climate is one of our Solar System's most perplexing mysteries. The planet was…

5 hours ago

Japan Launches the First Wooden Satellite to Space

Space debris, which consists of pieces of spent rocket stages, satellites, and other objects launched…

6 hours ago

You Can Build a Home Radio Telescope to Detect Clouds of Hydrogen in the Milky Way

If I ask you to picture a radio telescope, you probably imagine a large dish…

10 hours ago

A Space Walking Robot Could Build a Giant Telescope in Space

The Hubble Space Telescope was carried to space inside the space shuttle Discovery and then…

1 day ago

New Report Details What Happened to the Arecibo Observatory

In 1963, the Arecibo Observatory became operational on the island of Puerto Rico. Measuring 305…

2 days ago

We Understand Rotating Black Holes Even Less Than We Thought

The theory of black holes has several mathematical oddities. Recent research shows our understanding of…

2 days ago